Time filter

Source Type

Mendoza, Argentina

Bonafede M.M.,CONICET | Valdez S.R.,CONICET | Valdez S.R.,Institute Ciencias Basicas | Campo Verde Arbocco F.,CONICET | And 4 more authors.
Neuroendocrinology | Year: 2011

Background/Aims: Progesterone (P 4) fall provoked by spontaneous or prostaglandin F2α (PGF2α)-induced luteolysis in late pregnant rats triggers a prolactin (PRL) surge 12-24 h later. Methods: To investigate the hypothalamic mechanism mediating this response, we determined expression of tyrosine hydroxylase (TH), PRL receptors (long form, PRLR long), estrogen-α (ERα) and ERβ, P 4 (PR) A and B receptors, and STAT5a, STAT5b, suppressors of cytokine signaling 1 (SOCS1), SOCS3 and CIS at mRNA (by semiquantitative and real-time RT-PCR) and protein (by Western blot only for TH, ERα and PRs) levels, and dopamine and DOPAC (by high-performance liquid chromatography) contents in the mediobasal hypothalamus (MBH) 24 h after luteolysis induced by a PGF2α analogue (cloprostenol, 25 μg/rat s.c. at 8 and 12 h on day 19 of pregnancy). Results: PGF2α treatment decreased circulating P 4 and estradiol and increased PRL and the estradiol/P 4 ratio. MBH DOPAC and DOPAC/dopamine ratio fell, indicating decreased dopaminergic transmission. PRLR long, PRB and ERα mRNA increased. ERα and PR proteins were not modified. However, TH protein and mRNA did not change. PRA, the small PR isoform, was much more abundant than PRB, the isoform considered to mediate P 4 genomic actions. STAT5a, SOCS1 and SOCS3 mRNA were also increased. Conclusion: The P 4 fall induced by PGF2α treatment induces PRL release through diminution in MBH dopaminergic transmission without change in TH expression. The increased PRLR along with elevated circulating PRL may be responsible for maintaining high TH expression through activation of short-loop feedback mechanisms, counteracting the effect of the fall in circulating P 4. In parallel, SOCS expression contributes to limit PRL signaling. Copyright © 2011 S. Karger AG, Basel. Source

Acena A.,Institute Ciencias Basicas | Anabalon A.,Adolfo Ibanez University | Astefanesei D.,Pontifical Catholic University of Valparaiso
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

We construct a general class of exact regular black hole solutions with toroidal horizon topology in five-dimensional anti-de Sitter gravity with a self-interacting scalar field. With these boundary conditions and due to the nontrivial backreaction of the scalar field, the no-hair theorems can be evaded so that an event horizon can be formed. The scalar field is regular everywhere outside the curvature singularity and it vanishes at the boundary where the potential is finite. We study the properties of these black holes in the context of AdS/CFT duality and comment on the dual operators, which saturate the unitarity bound. We present exact expressions for the beta function and construct a c-function that characterizes the renormalization-group flow. © 2013 American Physical Society. Source

Cortes R.N.F.,CINVESTAV | Martinez M.G.,CINVESTAV | Guzman I.V.,Institute Ciencias Basicas | Llano S.L.A.,Centro Universitario do Postal 76010 | And 2 more authors.
Cereal Chemistry | Year: 2014

The objective of this study was to develop with thermoplastic extrusion amaranth starch derivatives and to characterize and evaluate their functionality as encapsulating agents of Bifidobacterium breve ATCC 15700 and Lactobacillus casei ATCC 334 during spray drying. The survival of both probiotics during storage at different water activities and at two storage temperatures, their viability in a food model system, and their tolerance to a simulated gastrointestinal tract were determined. Native amaranth starch was chemically modified to obtain phosphorylated, acetylated, and succinylated starch. Starch derivatives were reduced in viscosity, and the solubility in water was increased. In general, the modified amaranth starches and control corn starch did not provide good protection to both probiotics during storage at 25°C. However, there was excellent viability during storage at 4°C for both probiotics. Microcapsules showed a uniform coverage of the cells. Storage for 35 days at 25°C of blends of oat with succinylated amaranth microcapsules with probiotics had a lower reduction. Also, this succinylated amaranth starch containing probiotics showed a higher resistance to simulated gastrointestinal conditions. The results with food model systems supported the applicability of the modified starches. © 2014 AACC International, Inc. Source

Fertility patches under woody plant canopies in desert ecosystems may occur because the extended root systems of trees and shrubs absorb nutrients and deposit them below plant canopies during litterfall. The final effect of woody plants on soil fertility depends on different processes that transform litter and liberate nutrients to the soil. The woody legume Prosopis flexuosa D.C. produces the highest amount of litter in the Monte desert, generating islands of fertility under its canopy. In this study, we analyzed the temporal dynamics of litter mass fell under P. flexuosa and experimentally relocalized in different microsites (under P. flexuosa, under the shrub Larrea divaricata, in the previous canopy area of cut P. flexuosa trees, and in exposed areas). We found the highest decrease of litter mass in winter, similar for all microsites, and a lower decrease and higher spatial heterogeneity in spring and summer. Our results suggest that litter dynamics in the Monte desert is mainly controlled by litter quality, because the highestlitter mass loss occurred immediately after the addition of litter, even under environmental conditions not favorable for biologic activity (i.e., cold and dry winter). Although the different microsites showed differences in litter mass dynamics, the total magnitude of litter mass changes was similar for all microsites, indicating that spatial heterogeneity in litter mass loss is not an important factor in generating spatial heterogeneity of soil fertility. Moreover, other factors, as litter relocalization by arthropods observed in our study and possibly wind and water, seem to play an important role in moderating the spatial differences of litterfall patterns caused by woody plants. Source

Bertoldi D.S.,Institute Ciencias Basicas | Bertoldi D.S.,CONICET | Miranda E.N.,Institute Ciencias Basicas | Miranda E.N.,CONICET | Fernandez Guillermet A.,Bariloche Atomic Center
Journal of Physics and Chemistry of Solids | Year: 2014

We present an integrated thermostatistical study of the Grüneisen parameter and its application to a quasiharmonic solid. This analysis comprises two parts. The first part considers the connections between different thermodynamic formulations of the Grüneisen parameter, including those arising from the Mie-Grüneisen formula and related equations of state. We also establish the most general consequences of the so-called Grüneisen's rule. In the second part, Grüneisen's rule is used to establish the thermostatistics of a solid that obeys the quasiharmonic approximation. Both cases are relevant to the application of fundamental microscopic models of the heat capacity of solids. © 2014 Elsevier Ltd. Source

Discover hidden collaborations